diff --git a/blockchain/validate.go b/blockchain/validate.go
index 19183aa9..85946611 100644
--- a/blockchain/validate.go
+++ b/blockchain/validate.go
@@ -224,10 +224,7 @@ func withinLevelBounds(reduction int64, lv int64) bool {
 		return false
 	}
 	reduction++
-	if ((reduction*reduction + reduction) >> 1) <= lv {
-		return false
-	}
-	return true
+	return ((reduction*reduction + reduction) >> 1) > lv
 }
 
 // CheckTransactionSanity performs some preliminary checks on a transaction to
diff --git a/btcec/genprecomps.go b/btcec/genprecomps.go
index f09ab311..ea40ceac 100644
--- a/btcec/genprecomps.go
+++ b/btcec/genprecomps.go
@@ -5,6 +5,7 @@
 // This file is ignored during the regular build due to the following build tag.
 // It is called by go generate and used to automatically generate pre-computed
 // tables used to accelerate operations.
+//go:build ignore
 // +build ignore
 
 package main
diff --git a/btcec/gensecp256k1.go b/btcec/gensecp256k1.go
index 1928702d..e079f553 100644
--- a/btcec/gensecp256k1.go
+++ b/btcec/gensecp256k1.go
@@ -4,6 +4,7 @@
 
 // This file is ignored during the regular build due to the following build tag.
 // This build tag is set during go generate.
+//go:build gensecp256k1
 // +build gensecp256k1
 
 package btcec
diff --git a/limits/limits_unix.go b/limits/limits_unix.go
index 7ebf8667..7972b05e 100644
--- a/limits/limits_unix.go
+++ b/limits/limits_unix.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
+//go:build !windows && !plan9
 // +build !windows,!plan9
 
 package limits
diff --git a/rpcclient/infrastructure.go b/rpcclient/infrastructure.go
index 592c0dde..aedf18b7 100644
--- a/rpcclient/infrastructure.go
+++ b/rpcclient/infrastructure.go
@@ -1382,6 +1382,7 @@ func dial(config *ConnConfig) (*websocket.Conn, error) {
 		// cases above apply.
 		return nil, errors.New(resp.Status)
 	}
+	resp.Body.Close()
 	return wsConn, nil
 }
 
diff --git a/signalsigterm.go b/signalsigterm.go
index 83165501..63bdb9c0 100644
--- a/signalsigterm.go
+++ b/signalsigterm.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
 // +build darwin dragonfly freebsd linux netbsd openbsd solaris
 
 package main
diff --git a/upnp.go b/upnp.go
index 402924f5..d07d5ce9 100644
--- a/upnp.go
+++ b/upnp.go
@@ -136,7 +136,7 @@ func Discover() (nat NAT, err error) {
 		return
 	}
 	err = errors.New("UPnP port discovery failed")
-	return
+	return nat, err
 }
 
 // service represents the Service type in an UPnP xml description.
@@ -269,7 +269,7 @@ func getServiceURL(rootURL string) (url string, err error) {
 		return
 	}
 	url = combineURL(rootURL, d.ControlURL)
-	return
+	return url, err
 }
 
 // combineURL appends subURL onto rootURL.